Chapter 3. Performance Criteria for BMP Groups Section 3.1 ...Chapter 3. Performance Criteria for...
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Chapter 3. Performance Criteria for BMP Groups Section 3.1 Storm Water Filtering Systems Definition: Practices that capture and temporarily store the V w and pass it through a filter bed of sand, organic matter, soil or other media. Filtered runoff may be collected and returned to the conveyance system, or allowed to partially exfiltrate into the soil. Design variants include: # F-1 surface sand filter # F-2 one-chamber underground sand filter # F-3 three-chamber underground sand filter # F-4 perimeter sand filter # F-5 vertical sand filter # F-6 organic filter # F-7 bioretention # F-8 roof downspout system Filtering systems are typically not to be designed to provide storm water detention (Qp 2 , Qp 15 , and / or Q f ), but they may be in some circumstances. Filtering practices shall generally be combined with a separate facility to provide those controls. However, in combined sewer areas, the three-chamber underground sand filter can be modified by expanding the first or settling chamber, or adding an extra chamber between the filter chamber and the clear well chamber to handle the detention volume, which is subsequently discharged at a pre-determined rate through an orifice and weir combination. 3.3
Transcript of Chapter 3. Performance Criteria for BMP Groups Section 3.1 ...Chapter 3. Performance Criteria for...
Chapter 3. Performance Criteria for BMP Groups
Section 3.1 Storm Water Filtering Systems
Definition: Practices that capture and temporarily store the Vw and pass it through a filter bed ofsand, organic matter, soil or other media. Filtered runoff may be collected andreturned to the conveyance system, or allowed to partially exfiltrate into the soil.Design variants include:
# F-1 surface sand filter# F-2 one-chamber underground sand filter# F-3 three-chamber underground sand filter# F-4 perimeter sand filter# F-5 vertical sand filter# F-6 organic filter# F-7 bioretention# F-8 roof downspout system
Filtering systems are typically not to be designed to provide storm water detention (Qp2, Qp15, and/ or Qf), but they may be in some circumstances. Filtering practices shall generally be combined witha separate facility to provide those controls. However, in combined sewer areas, the three-chamberunderground sand filter can be modified by expanding the first or settling chamber, or adding anextra chamber between the filter chamber and the clear well chamber to handle the detention volume,which is subsequently discharged at a pre-determined rate through an orifice and weir combination.
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Chapter 3. Performance Criteria for BMP Groups
F-1 Figure 3.1 Example of Surface Sand Filter F-1
Source: Adapted from MDE, 2000
Surface sand filters can serve the largest drainage area of all the filtering systems.
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Chapter 3. Performance Criteria for BMP Groups
F-2 Figure 3.2 Example of One-Chamber Underground SF F-2
The one-chamber underground sand filter is an option for providing Vw on sites with lessthan 10,000 ft2 of impervious area where space or land prices are at a premium.
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Chapter 3. Performance Criteria for BMP Groups
F-3 Figure 3.3a Example of Three-Chamber Underground Sand Filter forSeparate Sewer Areas
F-3
The three-chamber underground sand filter is an option for providing Vw where space or landprices are at a premium.
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Chapter 3. Performance Criteria for BMP Groups
F-3 Figure 3.3b Example of Three-Chamber Underground Sand Filter forSeparate Sewer Areas
F-3
The three-chamber underground sand filter is an option for providing Vw where space or landprices are at a premium.
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Chapter 3. Performance Criteria for BMP Groups
F-3 Figure 3.3c Example of Three-Chamber Underground Sand Filter forSeparate Sewer Areas
F-3
The three-chamber underground sand filter is an option for providing Vw where space or landprices are at a premium.
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